Personally, I'd wait until you can buy a new rig.
That motherboard just doesn't give you enough headroom for buying a decent CPU that betters your old one.
This is what it supports:
Socket A for AMDŽ Athlon™ XP/ Athlon™/ Duron™ 600MHz - 2.8GHz+
You could buy a new motherboard, and get a much better CPU, which will be more worthwhile, for example a dual core X2 AMD, or an Intel Core 2 DUO.
The problems though start occuring here. For example, your new graphics card.
You see, your new video card is AGP only, which would limit your options when buying a new motherboard, since new motherboards now opt for PCI Express for graphics, though there are some AGP motherboards still around.
Your new memory would set you back the most though, since its only SD-RAM, which is very behind the times now, as new motherboards and also fairly old ones I'm afraid, opt for DDR RAM which is a faster alternative.
By a new system, what do you mean? Would you want to port the graphics/memory over to it?
If so, your options are limited I'm afraid